Enhancing Position Verification in Multi-Node Quantum Networks

Quantum position verification (QPV) is emerging as a promising application for quantum networks, leveraging spatial and quantum information to verify locations. However, current discussions on QPV protocols are largely confined to perfect experimental setups and one-dimensional scenarios. To address this gap, we extend the $\mathbf{QPV}_{BB84}^{f}$ protocol to two dimensions. First, we define the requirements for the 2D QPV task and assess its performance under real-world constraints, which potentially expose the system to external attacks. To strengthen the protocol against these vulnerabilities, we study the 'danger zones', defining a region in spacetime within which attackers can manipulate these real-world constraints to convince verifiers. We then develop two algorithms to implement this theory: the Verifiable Vertices Selection algorithm, which identifies nodes that can validate their locations with designated verifiers, and the Malicious Prover Location Identification algorithm, which determines the ‘danger zone’ around the prover. Finally, we present a case study to demonstrate the conceptual implementation of the protocol. Our findings advance the development of secure and practical QPV protocols while highlighting the potential of quantum networks in the noisy intermediate-scale quantum (NISQ) era.